Ive been wondering this for a while and then I saw Spaze's helm and I been thinking. What if you did a very good job on your armor (Darths helm quality) could you use that as a base for your molded armor? Because personally I suck at sculpting.
if you put the work ammount spase put in, your going to spend the samet of money as scultping and molding your own armor, but if your not very good with the sculpting tools, then I'd say yes you can make a good set of armor this way, the only bad part is, sculpting from clay to plaster to plastic is always superior quality, but spase, I'd say his is a acception, if i was to see a normal pep helmet, i'd know it's pepakura, if I saw spase's I would think twice if it was pep or not.
So yes you can make armor, but still you;d need 800-1400 dollars for molding.